My atiel is squinting one eye and rubbing it against herself while preening. whats happening?

When atiels do that they're usually just trying to get something out of their eye by rubbing it against themselves. My atiels do the same thing if they get something stuck to their eye or in it. If she's been doing this for a while though I'd examine her eye and see if there's something stuck in there she can't get out. And if there's nothing you can see and she keeps doing this I'd take her to the vet cuz she could have a very serious medical problem.